September 6, 2011

Ask Mister Math Person

Dave Barry had a running bit called "Ask Mister Language Person," in which he would dispense grammatical advice as if the rules of grammar were the common uses of the language rather than the real ones. So, for instance, he would dispense advice like this, under "Tips for Writer's":

Dear Mister Language Person: What is the purpose of the apostrophe?

Answer: The apostrophe is used mainly in hand-lettered small business signs to alert the reader than an S is coming up at the end of a word, as in: WE DO NOT EXCEPT PERSONAL CHECK'S, or: NOT RESPONSIBLE FOR ANY ITEM'S.

Via Dean Baker, I see that USA Today is trying out the same concept in a column called "Math tips for the rest of us." Only it's not satire:

That raise actually might not be as good as it looks. The extra money is nice, but it could very well bump you into the next tax bracket, possibly leaving you with less money than you had before the raise. Better benefits, such as medical, can save you money while keeping you in the same tax bracket.

Good God, no. This is completely false. The income tax bracket is graduated, meaning that when you move into a higher bracket, only the income above that level is taxed as a higher rate. It is not "possibly" the case that a raise will leave with with less money after taxes. It is never the case.

Lots of people fail to understand this concept, which is understandable. Even many political reporters fail to understand it. But in a column devoted to correcting misunderstandings about math? I don't know what to say.